Heat has long been used to modify and reshape collagen beneath the surface of the skin. Egyptians used salt, oil and alabaster to improve skin texture and Turks used fire to singe the surface of the skin. In the twentieth century, chemical peels implementing phenol and trichloacetic acid were introduced to reduce wrinkles and remove other anomalies of the skin. Lasers, such as carbon dioxide lasers, were also developed and used for the reduction or elimination of wrinkles, such as periorbital wrinkles, and other anomalies of the skin. Such methods were more or less effective in reducing or eliminating wrinkles by providing energy in the form of heat to the subreticular dermis between the epidermis and the dermis of an individual's skin. Heat stimulates release of factors that promote new collagen growth and a thicker healthier matrix of elastins and collagen to provide a younger looking skin. However, these techniques result in removal, destruction or damage to the epidermis proximate the area in which heat is applied to the subreticular dermal layer. The damage or destruction of the epidermis results in redness, loss of body fluid and a greater potential for infection.
For example, with lasers, laser light energy is used to heat tissue beneath the epidermis, but the laser light energy must pass through the epidermis on its way to the treatment area. This laser light energy is absorbed by the epidermis as it passes therethrough and generates unwanted heat that effectively ablates the epidermal layer in the area of treatment. After time, the epidermis heals and grows back over the treatment area.
Attempts have been made to minimize injury to the epidermis by removing heat from the epidermal area proximate the area of treatment. This is typically accomplished by delivering a coolant to the epidermis at the area where it is penetrated by the laser beam. However, this adds to the complexity of the equipment and the procedure.
Additionally, refractive errors, such as nearsightedness and farsightedness, can be reduced or corrected by reshaping the cornea of an eye. There are currently many methods for reshaping the cornea, including laser radial keratotomy and scalpel radial keratotomy. One problem with these procedures, particularly in correcting farsightedness, is the difficulty of gauging the effects of making incisions in the corneal surface.
One new technique involves heating the middle of the cornea in a radial pattern with a holmium laser. The heating causes the central cornea to bulge forward, thereby temporarily correcting for farsightedness. Unfortunately, the effect of the holmium laser alone is not permanent. Moreover, it is difficult to contain the laser to only those areas that are to be heated. Most energy sources for providing heat, such as the holmium laser, pulsed infrared light sources and even low wavelength lasers having wavelengths on the order of 1320 nanometers, are absorbed first by the outermost epithelial layer of the cornea before reaching the inner layers of the cornea where the desired reshaping should occur. The absorption of energy by the epithelial layer causes damage to the epithelium that results in pain and permeability to bacteria.
It would be advantageous to have a system for permanently reshaping the sublayers of tissue to correct surface layer defects.